To ask how many times something happens, start with the frame How often do or How often does, then the rest of the question.
How often + do / does
How often do you exercise?
How often does she visit?
How often do they play football?
Try it: ___ you go to the gym? (How often do / How often / How often are) Answer: How often do — The frame needs do after "How often": How often do you go? Without it ("How often you go?") the question is unfinished.
do or does?
Inside the frame, choose like any question: you, we, they take do; he, she, it take does.
How often do you cook?
How often does he cook?
How often do they cook?
Not "How often does you cook?" — say "How often do you cook?". you takes do. Save does for he, she, it.
Try it: How often ___ Amina visit her family? (does / do / is) Answer: does — Amina is one person (she), so the frame takes does: How often does Amina visit? ("do" is for you/we/they.)
Answering with a frequency
Answer with how many times, not a single day: every day, twice a week, usually, never.
How often do you exercise? Three times a week.
How often does she visit? Every weekend.
How often do they meet? Usually on Fridays.
Not "How often do you go? On Monday." — say "How often do you go? Every Monday.". "How often" asks how many times, so answer with a frequency like every Monday.
Try it: How often do you play tennis? Pick the natural answer. (Twice a week. / At the park. / Yes, I do.) Answer: Twice a week. — "How often" asks how many times, so answer with a frequency: Twice a week. "At the park" answers where; "Yes, I do" answers a yes/no question.
Use do / does, not is / are
For an action (go, work, eat), the frame uses do / does. Don't use is / are here.
How often do you travel?
How often does he call?
How often do they visit?
Not "How often you travel?" — say "How often do you travel?". Don't drop the do. An action word like travel needs do in the frame, not is / are.
Try it: How often ___ you eat out? (do / are / is) Answer: do — An action word like eat needs do: How often do you eat out? Save are for a feeling word, as in How often are you tired?
Try it: Ask Hiroshi about his habit. How often ___ he take the bus? (does / do / is) Answer: does — Hiroshi is one person (he), so the frame takes does: How often does he take the bus? (he/she/it → does.)